Image Generation

Nano Banana and Nano Banana Pro are image-generation steps powered by Google's Gemini image models.

• Nano Banana — Gemini 2.5 Flash Image. Fast generation at 1024px, with customizable aspect ratios.
• Nano Banana Pro — Gemini 3 Pro Image. Professional quality with resolutions up to 4K (1K / 2K / 4K).

💡 Find them in Steps → Actions → Image Models → Gemini.

Configuration

💡 Choosing an Output Format: Use Download URL when you want to display or share the image (it gives you a plain link you can embed or hand to a user). Use Base64 when a downstream step needs the raw bytes inline.

Output

Each step returns a GeminiGenerateImageResponse:

{
  "Images": [
    {
      "ImageUrl": "https://.../signed-blob-url",
      "ImageDataBase64": null,
      "MimeType": "image/png"
    }
  ],
  "Message": "…",
  "TotalCount": 1
}

• Images[] — One entry per generated image. Each has:
  • ImageUrl — the signed download URL (when Output Format = Download URL).
  • ImageDataBase64 — the base64-encoded bytes (when Output Format = Base64).
  • MimeType — e.g. image/png.
• Message — any text the model returned alongside the image.
• TotalCount — number of images generated.

Displaying the image in chat

Wire a Message Formatter step after Nano Banana:

Input  →  Nano Banana  →  Message Formatter  →  Output

1. On the Nano Banana step, set Output Format → Download URL (and, if you want the link to stay valid, set URL Expiry → Perpetual).

2. In the Message Formatter, use markdown's image syntax pointing at the step's ImageUrl:

   *[missing image: image]*

   • Inputs.Nano_Banana refers to the upstream step by its title, with spaces replaced by underscores (Nano Banana → Nano_Banana, Nano Banana 1 → Nano_Banana_1). See Variables for the naming rules.
   • .Output.Images[-1] grabs the most recently generated image ([-1] is the last item); use [0] for the first.
   • *[missing image: alt]* is markdown's image tag, so the chat surface renders the picture inline.

Add a download link. Because Download URL gives a real, shareable link, reuse the same ImageUrl in a markdown link (drop the leading !) to offer a click-to-download option:

*[missing image: image]*

[⬇️ Download image]({{Inputs.Nano_Banana.Output.Images[-1].ImageUrl}})

💡 Using Base64 output instead? Embed it as a data URI rather than a plain URL:

*[missing image: image]*

Troubleshooting

The image won't display / the link is empty

• The Message Formatter references ImageUrl, but the step is set to Base64. Switch Output Format → Download URL, or embed the base64 data URI instead (see above).

The variable doesn't resolve

• Check the step title in the token. The default step Nano Banana is referenced as Inputs.Nano_Banana; spaces become underscores, and a numbered duplicate like Nano Banana 1 becomes Nano_Banana_1. The token must match the title exactly.

The download link stops working after a while

• The signed URL expired. Increase URL Expiry, or set it to Perpetual for a non-expiring link.

Authentication errors

• Either select a valid Google API Key credential on the step, or leave the credential blank to fall back to the Airia Key.